(Redirected from Ancient weights and measures)A 'system of measurement' is a set of units which can be used to specify anything which can be measured. Some quantities are designated as fundamental units meaning ''all other needed units can be derived from them''. In most systems,
length (distance),
weight, and
time are ''fundamental quantities''; or as has been now accepted as better in science and engineering, the substitution of
mass for
weight, as a better more basic
parameter. Some systems have changed to recognize the improved relationship, notably the
1824 legal changes to the
Imperial system.
Later science developments showed that either
electric charge or
electric current must be added to complete ''the minimum set of fundamental quantities'' by which all other
metrological units may be defined. Other quantities, such as
power,
speed, etc. are derived from the fundamental set; for example, speed is distance divided by time. Historically a wide range of units were used for the same quantity; for example, in several cultural settings, length was measured in
inches,
feet,
yards,
fathoms,
rods,
chains,
furlongs,
miles,
nautical miles,
leagues, with conversion factors which are not simple powers of ten or even always simple fractions.
Nor were they necessarily the same units (or equal
units) between different members of similar cultural backgrounds, the
British Empire no longer owned the
United States, and of the
later British derived societies about half repudiated the
British Crown just like the United States did a century-and-a-half earlier. It must be understood by the modern reader that historically, measurement systems were perfectly adequate within their own cultural
milieu, and ''the understanding'' that a better more universal system (based on more rationale and fundamental units) only gradually spread with the maturation and appreciation of the rigor characteristic of
Newtonian physics. Moreover, changing one's measurement system has real fiscal and cultural costs.
Once the analysis tools within that field were appreciated and came into widespread use in the nascent sciences, especially in the utilitarian subfields of
applied science like
civil and
mechanical engineering, conversion to a common basis had no impetus. It was only after the appreciation of these needs and the appreciation of the difficulties of converting between numerous national customary systems became widespread could there be any serious justification for an international effort of standardization. Credit the
French Revolutionary spirit for taking the first significant and radical step down that road.
In antiquity, ''systems of measurement'' were defined locally, the different units were defined independently according to the length of a king's thumb or the size of his foot, the length of stride, the length of arm or per custom like the weight of water in a keg of specific size, perhaps itself defined in ''hands'' and ''knuckles''. The unifying characteristic is that there was ''some definition'' based on ''some standard'', however egocentric or amusing it may now seem viewed with eyes used to modern precision. Eventually ''
cubits'' and ''
strides'' gave way under need and demand from merchants and evolved to ''customary units.
In the
metric system and other recent systems, a single basic unit is used for each fundamental quantity. Often secondary units (multiples and submultiples) are used which convert to the basic units by multiplying by powers of ten, i.e., by simply moving the
decimal point. Thus the basic
metric unit of length is the
metre or
meter; a distance of 1.234 m is 1234.0 millimetres, or 0.001234 kilometres.
Metric system
A baby bottle that measures in all three measurement systems—Imperial (U.K.), U.S. Customary, and metric.
s of units have evolved since the adoption of the first well-defined system in
France in
1791. During this evolution the use of these systems spread throughout the world, first to the non-English-speaking countries, and more recently to the English speaking countries.
Multiples and submultiples of metric units are related by powers of ten; the names for these are formed with
prefixes. This relationship is compatible with the decimal system of numbers and it contributes greatly to the convenience of metric units.
In the early metric system there were two fundamental or base units, the
metre and the
gram, for length and mass. The other units of length and mass, and all units of area, volume, and compound units such as density were derived from these two fundamental units.
Mesures usuelles (
French for ''customary measurements'') were a system of
measurement introduced to act as compromise between the
metric system and traditional measurements. It was used in
France from
1812 to
1839.
A number of variations on the metric system have been in use. These include
gravitational systems, the
centimetre-gram-second systems (cgs) useful in science, the
metre-tonne-second system (mts) once used in the
USSR and the
metre-kilogram-second system of units (mks) most commonly used today.
The current international standard metric system is the
International System of Units (''Système international d'unités'' or SI) It is an mks system based on the
metre,
kilogram and
second as well as the
kelvin,
ampere,
candela, and
mole.
The
SI includes two classes of units which are defined and agreed internationally.
The first of these classes are the seven
SI base units for length, mass, time, temperature, electric current, luminous intensity and amount of substance. The second of these are the
SI derived units. These derived units are defined in terms of the seven base units. All other quantities (e.g. work, force, power) are expressed in terms of
SI derived units.
Imperial and U.S. customary units
Both the
Imperial units and
U.S. customary units derive from earlier
English units. Imperial units were mostly used in the
British Commonwealth and the former
British Empire. They are still used in common household applications to some extent and so are also sometimes called 'common units', but have now been mostly replaced by the
metric system in
commercial,
scientific, and
industrial applications.
Contrarily, however,
U.S. customary units are still the main system of measurement in the
United States. While some steps towards
metrication have been made (mainly in the late
1960s and early
1970s), the customary units have a strong hold due to the vast industrial infrastructure and commercial development. The effort is proceeding slowly due to the overwhelming financial cost of converting the existing infrastructure. U.S. companies which trade internationally are more likely to use the metric system due to international standards and certifications such as
ISO9000. The metric system is preferred in certain fields such as
science,
medicine and
technology. The building profession uses US customary units, though architects working internationally are increasingly adapting to the metric system.
These two systems are closely related. There are, however, a number of
differences between them. Units of length and area (the
inch,
foot,
yard,
mile etc.) are identical except for surveying purposes. The
Avoirdupois units of mass and weight differ for units larger than a
pound (lb.). The Imperial system uses a stone of 14 lb., a long
hundredweight of 112 lb. and a long
ton of 2240 lb. The stone is not used in the U.S. and the hundredweights and tons are short being 100 lb. and 2000 lb. respectively.
Where these systems most notably differ is in their respective units of volume. A U.S.
fluid ounce (fl. oz.) is slightly larger than its Imperial equivalent (the former being approximately 29.6
millilitres (ml) and the latter 28.4 ml). However, as there are 16 U.S. fl. oz. to a U.S.
pint as opposed to the 20 Imperial fl. oz. per Imperial pint, these pints are quite different in volume. The same is true of
quarts,
gallons, etc. Six U.S. gallons are a little less than five Imperial gallons.
Mentioned above was the
Avoirdupois system which has served as the general system of mass and weight. In addition to this there are the
Troy and the
Apothecaries' systems. Troy weight was customarily used for
precious metals,
black powder and
gemstones. The troy ounce is the only unit of the system in current use; it is used for precious metals. Although the troy ounce is larger than its Avoirdupois equivalent, the pound is smaller. The obsolete troy pound was divided into twelve ounces opposed to the sixteen ounces per pound of the Avoirdupois system. The Apothecaries' system; traditionally used in
pharmacology, now replaced by the metric system; shares same pound and ounce as the troy system but with different further subdivisions.
Natural units
Natural units are
physical units of measurement defined in terms of universal
physical constants in such a manner that some chosen physical constants take on the numerical value of one when expressed in terms of a particular set of natural units. Natural units are natural because the origin of their definition comes only from properties of
nature and not from any human construct. Various systems of natural units are possible. Below are listed some examples.
★
Geometric unit systems are useful in
relativistic physics. In these systems the base physical units are chosen so that the
speed of light and the
gravitational constant are set equal to unity.
★
Planck units are a form of geometric units obtained by also setting
Boltzmann's constant, the
Coulomb force constant and
Dirac's constant to unity. They might be considered unique in that they are based only on properties of
free space rather than any prototype, object or particle.
★
Stoney units are similar to Planck units but set the
elementary charge to unity and allow Dirac's constant to float.
★
"Schrödinger" units are also similar to Planck units and set the elementary charge to unity too but allow the speed of light to float.
★
Atomic units (au) are a convenient system of units of measurement used in
atomic physics, particularly for describing the properties of
electrons. The atomic units have been chosen such that the fundamental electron properties are all equal to one atomic unit. They are similar to "Schrödinger" units but set the
electron mass to unity and allow the gravitational constant to float. The unit
energy in this system is the total energy of the
electron in the
Bohr atom and called the
Hartree energy. The unit length is the
Bohr radius.
★
Electronic units are similar to Stoney units but set the
electron mass to unity and allow the gravitational constant to float. They are also similar to Atomic units but set the speed of light to unity and allow Dirac's constant to float.
★
Quantum electrodynamical units are similar to the electronic system of units except that the
proton mass is normalised rather than the electron mass.
Non-standard units
Non-standard measurement units, sometimes found in books, newspapers etc., include:
Area
★ The (American)
football field, which has a playing area 120
yards long by 53 1/3 yards wide. This is often used by the
American public media for the sizes of large buildings or parks: easily walkable but non-trivial distances. Note that it is used as a unit of length (120 yards) or area (6,400 sq yd).
★ British media also frequently uses the
football pitch for equivalent purposes, although
Association Football (Soccer) pitches are not of a fixed size, but instead can vary within defined limits (100-130 yards long, and 50-100 yards wide, giving an area of 5,000 to 13,000 sq yd). Example:
HSS vessels are aluminium catamarans 'about the size of a football pitch'... - Belfast Telegraph 23 June 2007
★ In the U.S. a small circular area is often described as "the size of a
dime". Example:
The "brain scope" developed at Duke University is inserted into a 'dime-sized hole' in the skull... -Science Daily
Energy
★ A ton of
TNT, and its multiples the
kiloton and the
megaton and the
gigaton. Often used in stating the power of very energetic events such as
explosions and
volcanic events and
earthquakes and
asteroid impacts. A
gram of TNT as a unit of
energy has been defined as 1000 thermochemical
calories = roughly 4184
joules.
★ The
Hiroshima atom bomb. Its force is often used in the
public media and popular
books as a unit of energy. (Its yield was roughly 13 kilotons.)
Mass
★ The weight of an
elephant. It is often used as a unit of weight in popular books about very big animals such as
dinosaurs. This unit needs to be defined, as the real weight of elephants varies much with age, sex and species.
★
Bald eagles. Example:
Largest Flying Bird ...Argentavis was no ostrich. Despite 'weighing as much as 16 bald eagles'... - National Geographic News 2 Jul 2007
Vertical distance
★ The "height of a London Bus" is used by British media to describe height. Example:
... tsunami three times the 'height of a London bus' that battered the north coast of New Guinea, wiping out four villages and killing more than 3,000 people - Guardian Unlimited
Volume
★ Nuts, fruit and vegitables are sometimes used to indicate volume. Example:
Facts about Arthritis ...The size of the nodules can range from that of a 'pea' to 'walnut' size. - The Desert Sun, Palm Springs CA 6 July 2007
★ Larger volumes can be indicated as being "the size of a house". Example:
Asteroids can range from 'the size of a house' to objects the size of Vesta. - Spaceflight Now quoting NASA press kit
Units of currency
A unit of measurement that applies to
money is called a
unit of account. This is normally a
currency issued by a
country or a fraction thereof; for instance, the
U.S. dollar and U.S. cent (1/100 of a dollar), or the
euro and euro cent.
ISO 4217 is the international standard describing three letter codes (also known as the currency code) to define the names of currencies established by the International Organization for Standardization (ISO).
Historical systems of measurement
Prior to the widespread adoption of the metric system many different systems of official measurement had been in use, many of these remain today, at least in part, in traditional or customary use. Many of these were related to some extent or other. Often they were based on the dimensions of the human body. When the world turned to trade between
city-states better systems were needed to enable that mercantile activity. Over time, the evolution continued as transportation continued to shrink the world, and so what was once an artifact of a pocket kingdom matured into something that was at least workable. Despite the growth and adoption of modern systems like
SI around the world for business and governance, such '''customary systems''' are still commonly used in day to day life for everyday ordinary household tasks around the world, most notably, in
cooking and
cookbooks.
Throughout the
history of measurement, many of the units that have been used in
Europe and around the
Mediterranean are variations on older systems originating in the
ancient Near East.
Middle Eastern systems of measurements
★
Arabic [1]
★
Egyptian
★
Hebrew
★
Maltese
★
Mesopotamian
★
Persian
South Asian systems of measurement
★
Harappan
★
Hindu
East Asian systems of measurement
★
Chinese
★
Japanese
Greco-Roman systems of measurement
★
Greek
★
Roman
Medieval European measurements
Medieval European systems of measurement evolved during the
Middle Ages (or European
Dark Ages) due to the agriculture-intensive way of life. These systems may also be referred to as ''feudal measurement systems''. The measurements were approximate and variable. The measures can be categorized by ever expanding commercial, political and religious spheres of influence.
Eastern European
In Eastern Europe traditional standards of measure were predominantly of Greek origin
★
Polish system
★
Romanian system
★
Russian system
★
Tatar system
Western and Northern European
In Western and Northern Europe traditional standards of measure were predominantly of Roman origin:
★
Danish system
★
Dutch system
★
English system
★
Finnish system
★
French system
★
German system
★
Norwegian system
★
Scottish system
★
Spanish system
★
Swedish system
Other historical systems of measurement
★
Pegu
See also
★
Megalithic yard
★
Pseudoscientific metrology
★
Weights and measures
★
Units of measurement
★
Conversion tables
★
Conversion of units
★
Approximate conversion of units
References
1. M. Ismail Marcinkowski, ''Measures and Weights in the Islamic World. An English Translation of Professor Walther Hinz's Handbook “Islamische Maße und Gewichte“'', with a foreword by Professor Bosworth, F.B.A. Kuala Lumpur, ISTAC, 2002, ISBN 983-9379-27-5. This work is an annotated translation of a work in German by the late German orientalist Walther Hinz, published in the ''Handbuch der Orientalistik'', erste Abteilung, Ergänzungsband I, Heft 1, Leiden, The Netherlands: E. J. Brill, 1970.
★ Tavernor, Robert (2007), ''Smoot's Ear: The Measure of Humanity'', ISBN 030-0124-92-9
External links
★
Dictionary of Units of Measurement
★
The Unified Code for Units of Measure
★
CLDR - Unicode localization of currency, date, time, numbers
★
Old units of measure
★
Measures from Antiquity and the Bible
★
A utiliy to Convert Different Units
★ Reasonover's Land Measures
A Reference to Spanish and French land measures(and their English equivalents with conversion tables) used in North America
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